The overall objective of this SCOR Program is to evaluate the cellular and molecular basis for asthma, in order to identify novel strategies for eventual therapeutic intervention. To achieve this goal, five research projects are proposed to address three key, interrelated facets of the asthmatic process: immune activation (of T-lymphocytes and eosinophils), airway smooth muscle (contraction and proliferation), and genetic predisposition. The comprehensive, mechanistic evaluations proposed require special expertise in the fields of immunology, cell signalling and cancer biology, molecular biology, and genetic epidemiology. An important feature of this SCOR proposal is that scientists from outside the traditional pulmonary community join with senior airways investigators to form a cohesive, interactive research program that incorporates a wide range of new perspectives, technologies, and approaches. PROJECT 1, T- cell Co-stimulation in Allergic Asthma, addresses the role of costimulatory molecules (e.g., CD28, B7-1, B7-2) in the generation and maintenance of allergic eosinophilic airway inflammation and non-specific bronchoconstrictor hyperresponsiveness in mice. PROJECT 2, Mechanisms and Consequences of Eosinophil Activation within Airways, tests the mechanisms by which cytokine or IgE exposure, or binding to endothelial cells or airway tissue matrix, upregulates eosinophil responses to immune stimulation, and how bioactive mediators released from eosinophils contract human airways. PROJECT 3, Inhibition of Airway Smooth Muscle Contraction, tests a novel strategy for preventing airway smooth muscle contraction through expression of an artificial minigene encoding an octapeptide that inhibits actin-myosin interaction and force generation. Expression of this exogenous gene is directed from a smooth muscle specific promoter derived from the murine SM22alpha gene. PROJECT 4, Signalling Mechanisms During Airway Smooth Muscle Proliferation, examines molecular mechanisms underlying the excess accumulation of smooth muscle in the bronchi of asthmatic individuals, specifically addressing the roles of mitogen activated protein kinases and of cyclin D(1) in airway smooth muscle proliferation. In PROJECT 5, Identification of Genes that Confer Asthma Susceptibility, asthma-linked chromosomal sites previously identified by the investigative team in the genetically inbred Hutterite population of North Dakota will be analyzed by fine mapping and sequence analysis to reveal gene alleles and DNA mutations that contribute genetic susceptibility to asthma phenotypes. These projects form a research program whose sum is greater than its parts, for: (i) they follow a logical thematic progression from basic immune mechanisms and eosinophilic inflammation into smooth muscle structure and function and onto identification of the genes responsible for asthma; (ii) they benefit from considerable exchange of expertise; and (iii) they take advantage of common core organizations (a Cell Isolation and Culture Core and an Administrative Core) that enhance research efficiency and productivity. Data derived from these collaborative studies will yield insights into the cellular and molecular mechanisms underlying asthma, and therefore should suggest strategies for novel therapeutic intervention.